1. Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
2. Section of Infectious Diseases, Department of Internal Medicine, McMaster University, Hamilton, Ontario, Canada
3. Department of Microbiology, St Luc Hospital, Montreal, Quebec, Canada
4. Laboratoire de sante publique du Quebec, Montreal, Quebec, Canada
5. Division of Infectious Diseases, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada